Cytomegalovirus (CMV) can be transmitted from the mother to the fetus and is a leading cause of sensorineural hearing loss (SNHL), which is a condition where the inner ear is unable to convert sound into nerve impulses to the brain. This hearing loss and its detrimental effect on language development contribute nearly $4 billion annually to the health care costs in the U.S. Unlike other types of SNHL, CMV induced hearing loss can be treated. Several clinical trials have demonstrated that antiviral therapy may prevent progressive hearing loss if administered early in life for severely affected (symptomatic CMV) infants. These promising findings have given rise to a debate regarding the best method for identifying and treating less affected but more numerous (asymptomatic CMV) infants with CMV. One approach is CMV testing only those newborns who fail their newborn hearing screening. This path has been advocated as a targeted option to identify those infants at greatest risk to develop progressive hearing loss. Utah is the first state to mandate this approach whereby infants under three weeks of age who fail their newborn hearing screening undergo CMV testing. Since we anticipate maximal benefit from antiviral therapy, we will compare the hearing, and language outcomes of asymptomatic CMV infected valganciclovir (VGC) treated and untreated infants identified via a hearinglosstargetedearlyCMVapproach(HT-CMV).Thisanalysiswillinformpublicpolicyandpotentiallyshift our current clinical practice regarding pediatric hearing loss evaluation. In the proposed work, the investigators will pursue two specific aims: (1) Compare the hearing and language outcomes of asymptomatic CMV-infected hearing-impaired treated to untreated infants via a multi-institutional double-blinded placebo controlled clinical trial. (2) To evaluate the safety of antiviral valganciclovir therapy for asymptomatic CMV-infected hearing impaired infants. This project is directly relevant to the mission of the NIDCD ?to support research evaluating approaches to the identification and treatment of communication disorders and patient outcomes .? More specifically, in the 2012?2016 NIDCD Strategic Plan, in the Priority Area of Hearing and Balance Research, Priority Area 4 includes comparative effectiveness research which will inform health care decisions.